Factors affecting xylene-contaminated air removal by the ornamental plant Zamioculcas zamiifolia

Fifteen plant species—Alternanthera bettzickiana, Drimiopsis botryoides, Aloe vera, Chlorophytum comosum, Aglaonema commutatum, Cordyline fruticosa, Philodendron martianum, Sansevieria hyacinthoides, Aglaonema rotundum, Fittonia albivenis, Muehlenbeckia platyclada, Tradescantia spathacea, Guzmania lingulata, Zamioculcas zamiifolia, and Cyperus alternifolius—were evaluated for the removal efficiency of xylene from contaminated air. Among the test plants, Z. zamiifolia showed the highest xylene removal efficiency. Xylene was toxic to Z. zamiifolia with an LC₅₀ of 3,464 ppm. Higher concentrations of xylene exhibited damage symptoms, including leaf tips turning yellow, holonecrosis, and hydrosis. TEM images showed that a low concentration of xylene vapors caused minor changes in the chloroplast, while a high concentration caused swollen chloroplasts and damage. The effect of photosynthetic types on xylene removal efficiency suggests that a mixture of Z. zamiifolia, S. hyacinthoides, and A. commutatum which represent facultative CAM, CAM, and C₃ plants, is the most suitable system for xylene removal. Therefore, for maximum improvement in removing xylene volatile compounds under various conditions, multiple species are needed. The effect of a plant’s total leaf area on xylene removal indicates that at lower concentrations of xylene, a small leaf area might be as efficient as a large leaf area.